The invention relates to a device for fastening and fixing components to a cylindrical wall.
In numerous technical applications, components have to be fastened and fixed to cylindrical wall contours. In the process, the components must be fixed in the radial, axial and circumferential directions. A typical example from turbomachine construction is the fastening of heat-protection shields to rotors or in casings. The object is normally achieved by virtue of the fact that shaped elements on the components to be anchored and counterparts which are made in the wall interlock and thus produce a positive-locking connection. In design terms, an attempt is made to use as few of these shaped elements as possible. A widespread solution is to fix the component in all three spatial directions with a single shaped element. However, with increasing demands on the definability of the installed position of the elements, the cost of producing such shaped elements increases considerably. For reasons of fitting (double fit, xe2x80x9chinge effectxe2x80x9d), the requisite accuracy of manufacture also increases out of proportion to the installation accuracy, which ultimately also reaches its practical limit with the solution cited.
At this point, the invention proposes to separate the fixing tasks in such a way that, for each spatial direction in which fixing has to be effected, there is in each case at least one shaped element, which has a well-defined accuracy of fit with its counterpart in this direction and has ample clearance in the other spatial directions.
The essence of the invention is therefore to allocate the fixing task in different spatial directions to different fastening elements. As a result, each fastening element and its respectively associated counterpart can be produced with the requisite accuracy in precisely this spatial direction without influencing the accuracy of fit in the other spatial directions in the process. In effect, this measure results in a reduced production and assembly cost.
If necessary, the fastening may be designed so as to be secure against tilting and/or rotation by two fastening elements being arranged for one spatial direction at locations which are as far away from one another as possible in a direction perpendicular to the tilting or rotation axis. With regard to a heat-protection shield, which constitutes an essentially two-dimensional structure without a considerable extent in the radial direction, that would mean arranging two radial and/or circumferential fixings at as large an axial distance apart as possible, or two axial fixings at as large a distance apart as possible in the circumferential direction.
Likewise, precisely in connection with the fixing of heat-protection shields to rotors or in the casings of turbomachines, it may be appropriate to attach a total of three radial fastening and fixing elements in an axial section, specifically two elements situated axially on the outside, which during normal operation radially fix the component to the wall, and a center element, which has a well-defined clearance with its counterpart in the radial direction. By this embodiment, the heat-protection shield can first of all freely deform in the radial direction in order to absorb thermal expansion as far as possible in a stress-free manner. In the event of excessive radial deformation, however, there is the risk of the heat-protection shield grazing against an opposite component moving in a relative manner. The resulting frictional heat in turn provides for self-amplification of the grazing, a factor which may consequently lead to damage to an entire turboset. In this case, the center mounting limits the possible radial deformation to the size which is provided as radial clearance for this mounting.
A device for fastening and fixing a component to a cylindrical wall comprises at least three pairs of elements, each pair of elements comprising a shaped first element and a respective counterpart shaped second element, each one of the first elements interlocking with one of the counterpart second elements. The first shaped elements are adapted and configured to be attached to the component and the second shaped elements are adapted and configured to be attached to the cylindrical wall, the first and second elements adapted and configured for fastening and fixing the component to the cylindrical wall. At least one pair of first and second elements is adapted and configured for fixing the component to the cylindrical wall in the radial direction in that the first shaped element has a defined accuracy of fit with its counterpart second element in the radial direction and has a clearance in the axial and circumferential directions. At least one pair of first and second elements is adapted and configured for fixing the component to the cylindrical wall in the axial direction in that the first shaped element has a defined accuracy of fit with its counterpart second element in the axial direction and has a clearance in the radial and circumferential directions. At least one pair of first and second elements is adapted and configured for fixing the component to the cylindrical wall in the circumferential direction in that the first shaped element has a defined accuracy of fit with its counterpart second element in the circumferential direction and has a clearance in the radial and axial directions. Further, the at least three pairs of elements can comprise at least two pairs of fixation elements for fixing the component in the radial direction, said at least two pairs of fixation elements being arranged axially spaced from each other, and at least one supplemental pair of elements is arranged axially between the at least two pairs of fixation elements, and said at least one supplemental pair of elements comprising a first shaped element and a second counterpart shaped element, wherein the first element of the supplemental pair has an arbitrary clearance with the second element of the supplemental pair in the axial and circumferential directions, and has a well-defined clearance with the second element of the supplemental pair in the radial direction.